Kuyilo lombane kunye nokuguqulwa kobugcisa, abasebenzi bombane bahlala bengazi ukuba bakhethe njani ngokwesayensi indawo enqamlezileyo yeentambo.Abasebenzi bombane abanamava baya kubala okwangoku ngokusekelwe kumthwalo wombane kwaye ukhethe indawo ye-cross-sectional yentambo ngokulula kakhulu;Umanyano lukhetha i-cable cross-section esekelwe kwifomula yombane;Ndingathi amava abo ayasebenza kodwa hayi ezenzululwazi.Kukho izithuba ezininzi kwi-Intanethi, kodwa zihlala zingaqondwa ngokwaneleyo kwaye kunzima ukuziqonda.Namhlanje ndiza kubelana nawe ngendlela yesayensi kunye nelula yokukhetha indawo enqamlezileyo yentambo.Kukho iindlela ezine zezihlandlo ezahlukeneyo.
Khetha ngokomthamo ovumelekileyo wexesha elide:
Ukuqinisekisa ukhuseleko kunye nobomi benkonzo yentambo, ubushushu bentambo emva kombane akufunekanga budlule ubushushu obuchaziweyo bexesha elide elivumelekileyo, eliyi-70 degrees yePVC insulated cables kunye ne-90 degrees ye-cross-linked polyethylene. iintambo ezigqunyiweyo.Ngokwalo mgaqo , kulula kakhulu ukukhetha ikhebula ngokujonga itafile.
Nika imizekelo:
Umthamo we-transformer wefektri yi-2500KVa kunye nokunikezelwa kwamandla yi-10KV.Ukuba iintambo ze-polyethylene ezifakwe emnqamlezweni zisetyenziselwa ukuzibeka kwibhulorho, kufuneka ibe yintoni indawo enqamlezileyo yeentambo?
Inyathelo 1: Bala ireyithingi yangoku 2500/10.5/1.732=137A
Inyathelo 2: Jonga incwadi yokukhetha intambo ukuze ufumane,
I-YJV-8.7/10KV-3X25 umthamo wokuthwala yi-120A
I-YJV-8.7/10KV-3X35 umthamo wokuthwala yi-140A
Inyathelo lesi-3: Khetha intambo ye-YJV-8.7/10KV-3X35 enamandla okuthwala angaphezu kwe-137A, enokuthi ihlangabezane neemfuno.Qaphela: Le ndlela ayiqwalasele iimfuno zokuzinza okuguquguqukayo kunye nokuzinza kwe-thermal.
Khetha ngokoqoqosho lwangoku:
Ukuqonda ngokulula ukuxinana kwangoku kwezoqoqosho, indawo enqamlezileyo yekhebula ichaphazela utyalo-mali lomgca kunye nokulahleka kwamandla ombane.Ukuze kugcinwe utyalo-mali, kuthenjwa ukuba i-cable cross-sectional area incinci;ukuze kuncitshiswe ilahleko yamandla ombane, kuthenjwa ukuba indawo enqamlezileyo yentambo inkulu.Ngokusekelwe kwiingqwalasela ezingentla apha, misela ingqiqo Indawo enqamlezileyo yekhebula ibizwa ngokuba yi-economic cross-sectional area, kwaye ukuxinana kwangoku okuhambelanayo kubizwa ngokuba yi-economic current density.
Indlela: Ngokweeyure zokusebenza zonyaka zesixhobo, jonga itafile ukuze ufumane ingxinano yangoku yezoqoqosho.Iyunithi: A/mm2
Umzekelo: Ukulinganiswa kwangoku kwesixhobo yi-150A, kwaye ixesha lokusebenza lonyaka liyi-8,000 iiyure.Iyintoni indawo enqamlezileyo yentambo engundoqo yobhedu?
Ngokutsho kwetheyibhile engentla i-C-1, kunokubonwa ukuba kwiiyure ze-8000, ubuninzi bezoqoqosho ngu-1.75A / mm2
S=150/1.75=85.7A
Isiphelo: Ummandla we-cable cross-sectional sinokukhetha ngokweenkcukacha zekhebula yi-95mm2
Khetha ngokokuqina kozinzo lwe-thermal:
Xa sisebenzisa iindlela zokuqala kunye neyesibini ukukhetha indawo ye-cable cross-sectional, ukuba ikhebula lide kakhulu, kuya kubakho ukuhla kwe-voltage ethile ngexesha lokusebenza kunye nokuqalisa.I-voltage kwicala lezixhobo iphantsi kunoluhlu oluthile, oluya kubangela ukuba izixhobo zifudumale.Ngokweemfuno ze "Manual yoMbane", ukuhla kwamandla ombane we-400V umgca awukwazi ukuba ngaphantsi kwe-7%, oko kukuthi, 380VX7% = 26.6V.Ifomula yokubala i-voltage drop drop (kuphela kuphela ukuhla kwamandla ombane okuchasayo kuqwalaselwa apha):
U=I×ρ×L/SS=I×ρ×L/U
Ukuhla kwamandla ombane e-U Ndingumlinganiselo obekiweyo wesixhobo.
Umzekelo: Umjelo olinganisiweyo wesixhobo se-380V yi-150A, usebenzisa intambo yobhedu yobhedu (ρ yobhedu = 0.0175Ω.mm2/m), ukuhla kwamandla ombane kufuneka kube ngaphantsi kwe-7% (U=26.6V), ubude bentambo Iimitha ezingama-600, yintoni indawo yentambo enqamlezileyo S??
Ngokwefomula S=I×ρ×L/U=150×0.0175×600/26.6=59.2mm2
Ukuqukumbela: Indawo ye-cable cross-sectional ikhethwe njenge-70mm2.
Khetha ngokokuqina kozinzo lwe-thermal:
1. Xa iintambo ze-0.4KV zikhuselwe ngokutshintsha komoya, iintambo eziqhelekileyo ziyakwazi ukuhlangabezana neemfuno zokuzinza kwe-thermal kwaye akukho mfuneko yokukhangela ngokwale ndlela.
2. Kwiintambo ezingaphezulu kwe-6KV, emva kokukhetha i-cable cross-sectional area usebenzisa le ndlela ingentla, kufuneka ukhangele ukuba ihlangabezana neemfuno zokuzinza kwe-thermal ngokwendlela elandelayo.Ukuba akunjalo, kufuneka ukhethe indawo enkulu enqamlezileyo.
Ifomula: Smin=Id×√Ti/C
Phakathi kwabo, i-Ti yithuba lokuqhawula i-circuit breaker, ethathwa njenge-0.25S, i-C yi-cable thermal stability coefficient, ethathwa njenge-80, kunye ne-Id yinqanaba lesithathu lexabiso le-short-circuit yangoku yenkqubo.
Umzekelo: Ungayikhetha njani indawo enqamlezileyo yentambo xa isixokelelwano esifutshane sesekhethi yangoku siyi-18KA.
Smin=18000×√0.25/80=112.5mm2
Isiphelo: Ukuba inkqubo ye-short-circuit current ifikelela kwi-18KA, nangona i-current rated current yesixhobo incinci, i-cable cross-sectional area ayifanele ibe ngaphantsi kwe-120mm2.
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Ixesha lokuposa: Sep-13-2023
